Rockfalls visible in orbiter images of Mars indicate that geologic activity occurred just a few million years ago and may be ongoing.

Date: 2015-10-07; view: 355.

Mars May Still Be Quaking

Pre- listening (3)

Mars has been the target of a lot of recent exploration. What do you know about it? What might this planet be experiencing now? What is Solar Corona?

Listening (3).

Fill in the blanks as you listen to the following texts.

What's shaking on Mars? A new study suggests that tremors _________ ________ __________ the Red Planet just millions of years ago. These earthquakes, well, Marsquakes, ___________ ___________ ___ __________ today. That would mean that Mars is not geologically dead, as is usually assumed.

A team of European scientists analyzed imagery of a Martian fault system from a NASA orbiter. In the high-resolution photos, the researchers _________ __________ individual boulders that have tumbled down cliffs near the fault.

They found that the most rockfalls, and the biggest boulders, were concentrated around one part of the fault system. That's what you ____________ __________ near the epicenter of a Marsquake. And it's not what you _________ __________ from a more mundane cause—avalanches caused by melting ice, for instance. The study appears in the Journal of Geophysical Research.

Because the fault system cuts through terrain that is just millions of years old, the Marsquakes themselves ________ also __________ __________ very recent. Some rockfalls appear so young that winds have not yet erased the tracks left by boulders rolling downhill.

Whether the Red Planet remains geologically active is uncertain. But rolling rocks support the idea that Mars is still rocking and rolling.

—John Matson